Method of assembling a dynamo-electric machine component

ABSTRACT

Stator designs have wide-mouth slots between adjacent poles. Wire coils with high slot fill conductivity are formed around the poles. In some designs, the wire coils are wave wound around the poles. Thick bar conductors can be used for making the wire coils. The wire coils may be inserted using nozzle dispensers or transferred from a pre-form mandrel. In other designs, the wire coils are pre-formed on transferable pockets that are then mounted on the poles. Optional pole extensions or shoes can be attached to the stator poles after the wire coils are formed around the poles.

This application is a continuation of U.S. application Ser. No.10/434,892, filed May 8, 2003, which claims the benefit of U.S.provisional application Ser. No. 60/380,893, filed May 14, 2002 and U.S.provisional application Ser. No. 60/396,406, filed Jul. 15, 2002. Theseprior applications are hereby incorporated by reference herein in theirentireties.

BACKGROUND OF THE INVENTION

The present invention relates to improved wire coil designs fordynamo-electric machine components (e.g., stators for electric motors,generators, or alternators) and to manufacturing solutions forimplementing such designs.

Dynamo-electric machines operate by exploiting the interaction ofrotating magnetic fields with a magnetic part or rotor. For example, acelectric motors include armatures or a configuration of insulated wirecoils in a stationary part or stator. Current flow through the wirecoils generates magnetic fields in the space of the stator. The wirecoils are wound around ferromagnetic cores or poles to enhance thestrength of the generated magnetic field. Stator casings are often madefrom ferromagnetic laminates. Longitudinal slots in the stator casingsusually define these poles. The poles generally are tooth-like crosssections that are rectangular or trapezoidal, but are invariablyprovided with cap-like lateral extensions or shoes at their top ends toenhance the concentration or passage of magnetic flux.

Flowing current of different phases through a progressive sequence ofcoils around the stator rotates the magnetic field generated in thestator. This rotating magnetic field imparts electromechanical torque tothe rotor and turns the electrical motor shaft on which the rotor ismounted.

The operational characteristics of a dynamo-electric machine depend onthe nature or properties of the generated magnetic field. Theseproperties are determined by the particular structure or design of theslots, poles, and the wire coils used. Design features such as the shapeof the slots (e.g., depth, widths, and curvatures) and the windingspecifications (e.g., wire size, turns, and slot fill ratio), affect notonly the performance and efficiency of the dynamo-electric machine, butare also relevant to dynamo-electric machine manufacturing costs andreliability.

Consideration is now being given generally to ways of providingsolutions for improving uniformity and reproducibility indynamo-electric machine component manufacture. Attention is directed toslot and pole shapes, and winding coil structures or designs, with aview to improve the performance of dynamo-electric machines, and toimprove manufacturing costs and reliability.

SUMMARY OF THE INVENTION

In accordance with the principles of the invention, dynamo-electricmachine components are designed for high slot fill conductivity.Conventional cap-like pole extensions are avoided, or optionally areinstalled after the wire coils are placed or inserted in the slots. Thewide mouth-slot designs provide unhindered access to the interiorportions of the slot. All regions or volumes of the slots are accessiblefor insertion or placement of wire coil turns. Thus greater slot fillconductivity can be achieved.

The inventive wide-mouth slot design may, for example, be used to makecompact, high current capacity poly-phase stators for automotivealternator applications.

Wire coils corresponding to each of the current phases may, for example,be wave wound around the stator poles. Conventional wire sizes may beused for the wire turns of the wire coils. optionally, thick barconductors can be used for making a wire coil with a designedcurrent-carrying capacity with fewer turns than is possible with smallersize wire.

The wire coils can be formed using a nozzle to dispense stretches ofwire conductors. The stator and the nozzle are moved relative to eachother to place conductor lengths generally along the path or shape ofthe desired wire coil. Conductor lengths placed along the slot passagesare then pulled or snapped into the slots by relative radial motion ofthe nozzle to insert the wire coil around the poles.

Alternatively, the wire coil conductors may first be preformed or shapedon a co-axial mandrel. The mandrel can have seats to hold a pre-formedwire coil. The mandrel seats can be aligned with the stator passages.Radial push or presser mechanisms built, for example, into the mandrelseats may be used to push transfer and press the pre-formed wire coilfrom the mandrel into the stator slots.

In some stator applications, parallel coil configurations (in whichindividual coils are wound around individual poles) are desirable. Theindividual wire coils may be installed as preformed wire coils. Thepre-formed wire coils may be made wound on (insulating material)pockets, and then transferred to surround the poles. In some cases, thepocket carrying a pre-formed wire coil itself may be moved ortransferred to surround a pole.

In an assembly line coil-winding workstation, a mandrel supportsmoveable pockets on a number of radial extensions. Flyer arms or otherwinding tools are used to pre-form wire coils in the supported pockets.The stator poles are then aligned with the radial mandrel extensions.Pockets holding the pre-formed wire coils on the radial mandrelextensions are then transferred on to the stator poles.

One or more workstations may be used to concurrently process fractionsof the number of wire coils required for a stator. Accordingly, thenumber of pockets/radial extensions on the mandrel in each of theworkstations corresponds to a fraction of the total number of the poles.Processing a limited number of wire coils at a workstation mayaccommodate the workspace or clearance requirements of common windingtools (e.g., flyer arms) in otherwise tight stator geometries orconfigurations. In a convenient arrangement, each workstation is used toprocess wire-coils for the poles associated with a specific currentphase. Thus, for a three-phase stator, three workstations are used.

Insulating covers may optionally be installed over the slot passages tomechanically retain the coil conductors in position. Similarly, optionalferromagnetic pole extensions designed to enhance passage of magneticflux through the poles can be installed after the wire coil has beeninserted.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the invention, its nature, and various advantageswill be more apparent from the following detailed description of thepreferred embodiments and the accompanying drawings, wherein likereference characters represent like elements throughout, and in which:

FIG. 1 is a partial plan view of an exemplary three-phase stator duringthe formation of wave wound conductor coils according to the principlesof this invention;

FIG. 2 is an illustrative planar projection of portions of one of thewave wound conductor coils of FIG. 1 exemplifying its waveconfiguration. (The partial plan view of FIG. 1 corresponds, forexample, to a view from direction 1-1 or from other similar directionsin FIG. 2);

FIG. 3 is a view similar to that of FIG. 1, showing the longitudinalconductor portions of a wire coil placed in the stator slots, inaccordance with the principles of this invention;

FIG. 4 is a view taken from direction 4-4 of FIG. 3, illustrating theuse of a wire delivery nozzle to insert conductors into the statorslots, in accordance with the principles of this invention;

FIG. 5 is a view taken from direction 5-5 of FIG. 4, schematicallyillustrating the relative radial motion of the wire delivery nozzlewhile inserting longitudinal conductor portions of the wire conductorsin the stator slots, and other motion while depositing conductorsegments or lengths on an axial face of the stator, in accordance withthe principles of this invention;

FIGS. 6 and 7 respectively show different slot cover assemblies that canbe placed over the stator slot openings to cover the inserted wireconductors, in accordance with the principles of this invention. FIGS. 6and 7 show an enlarged view of a slot of FIG. 3 with the slot coveringsin place over the slot;

FIG. 8 is a perspective view of the slot cover assembly of FIG. 7, inaccordance with the principles of this invention. FIG. 8 is taken fromdirection 8 of FIG. 7;

FIGS. 9 and 10 show another slot cover assembly, in accordance with theprinciples of this invention. FIG. 9 shows portions of this slot coverassembly placed over three of the slots of FIG. 3. FIG. 10 is a viewtaken from direction 10-10 of FIG. 9;

FIG. 11 is a perspective view of a mandrel and flyer arm arrangementwhich is used for pre-forming wire coils in moveable pockets, inaccordance with the principles of this invention;

FIG. 12 is a planar partial view of the mandrel and flyer armarrangement of FIG. 11. FIG. 12 additionally shows a stator aligned withthe mandrel and shows the pockets with the pre-formed wire coils beingmoved onto the stator poles, in accordance with the principles of thisinvention;

FIG. 13 shows the moving pockets of FIG. 12 installed on the statorpoles in accordance with the principles of this invention; and

FIG. 14 is an enlarged cross sectional view of area 40 of FIG. 13illustrating the abutment of pole extensions to the pole, and forclarity only, a few of the of the wire turns in the corner region.

In several of the accompanying drawings, which show sectional views,hatching or shading of various sectional elements have been omitted forclarity. It will be understood that this omission of hatching or shadingin the drawings is for the purpose of clarity in illustration only.

DETAILED DESCRIPTION OF THE INVENTION

In order that the invention herein described can be fully understood,the subsequent description is set forth in the context of themanufacture of polyphase, multiple-pole stators.

An inventive stator design is described herein with reference to stator10 shown in FIG. 1. The casing of stator 10 may, for example, beassembled by conventional methods from shaped ferromagnetic laminates.Lamination slots (e.g., slots 11, 12, 13, 14) running along the innersurface of the casing define the stator poles around which wire coilsare formed.

Stator 10 may have the phase and pole/slot configurations that arecommonly used in stators for automobile alternator applications. Forexample, stator 10 may have a three-phase, 36 slot configuration.

In a common automobile alternator, each of the thirty-six stator slotsis associated with a specific current phase. Adjacent slots areassociated with the respectively adjacent current phases. Thisassociation progressively repeats itself in sequence around the stator(as the number of slots exceeds the number of different current phases).Thus, three intercalated sequences of slots are associated with thefirst, second and third current phases. Each sequence is 12 slots longand has a pitch or interval of three slots. For example, the sequence(1, 4, 7, . . . , and 34) corresponds to the first phase, while thesequence (2, 5, 8, . . . , and 35) corresponds to the second phase.

Rotating magnetic fields are generated by flowing current of appropriatephase through wire coils placed in the slots. By design the wire coilsmay have different winding patterns (e.g., serial or parallel) aroundthe stator poles.

In stator 10 described herein, for purposes of illustration, each wirecoil corresponding to a current phase is wound or connected in series ina “wave configuration” (see e.g., FIG. 2) with longitudinal wireportions (e.g., portions 16 a and 17 a) running in the slots of thesequence associated with the current phase. Horizontal wire segments orlengths (e.g., 16 b and 17 b) electrically connect in series thelongitudinal wire lengths placed in the slots. These horizontal wirelengths are placed along the top or bottom axial faces of stator 10.With the use of this wave winding configuration, each of the threecurrent phases corresponds to a single wire coil around the stator.Thus, three-phase stator 10 has three wire coils.

In conventional stators each of the stator wire coils may includeseveral wire turns or filaments depending on the wire size used.Conventional manufacturing methods and apparatus for assembly of statorshaving a wave configuration of wire coils are disclosed, for example, inBarrera U.S. Pat. No. 4,512,376, and in Cardini et al. U.S. Pat. No.5,845,392. It will, however, be understood that the invention disclosedherein is not limited to stators with wave wound coils, but is alsoapplicable to other types of dynamo-electric machine components and toother types of winding configurations or patterns.

In inventive stator 10, one or more thick bar conductors are used tomake the stator wire coils. The use of thick bar conductors may avoidthe limitations associated with the conventional use of small size wiresto make the stator coils. For example, the use of thick bar conductorsmay simplify wire coil manufacture by reducing the number of wire turnsrequired to fabricate a wire coil with a desired current-carryingcapacity. Also, the use of thick bar conductors may advantageouslyincrease the conducting fill of the stator slots. High conducting fillsmay improve stator performance characteristics, and allow theconstruction of more compact stators than may be possible using coilsmade with smaller wire size. Compact stators may be preferred, forexample, for automobile alternators.

With reference to the exemplary three-phase stator 10 shown in FIG. 1,the first phase coil may be made from two thick bar conductors 16 and 17that have diameters comparable to the width (W) of stator slot passagesP. FIG. 1 shows longitudinal conductor portions 16 a and 17 a of thefirst phase coil that are respectively designated for placement in slots11 and 14. Similar longitudinal conductor portions are designated forplacement in other slots around the stator that are associated with thefirst current phase (not shown). FIG. 1 also shows phantomrepresentations of conductor lengths 16 b and 17 b. These conductorlengths connect longitudinal conductor portions 16 a and 17 a to provideelectrical continuity to the first phase coil around the stator.Conductor lengths 16 b and 17 b are designated to run across the topaxial face 10′ of stator 10. Similar conductor lengths that lead toconductor portions 16 a and 17 a from adjoining (first phase) slots aredesignated to run across the bottom axial face (not shown). Also forclarity in FIG. 1, conductors of the second and the third phase coils,which are respectively designated for placement in slots 12 and 13 arenot shown.

Stator 10 poles are suitably designed to accommodate insertion of thethick bar conductors in the stator slots. For example, stator 10 polesare designed to increase the width (W) of the openings leading to slotpassages P. To accomplish this the conventionally used cap-like poleexpansion portions or shoes are omitted or reduced from the laminatecasing that is used in stator 10. FIG. 1 shows, for example, stator 10poles with reduced expansion portions (corners C). With the reduced oromitted pole expansion portions, the slot opening widths W are about thesame as the general widths of slot passages P over their entire depths.These unconventionally enlarged slot opening widths W allow unrestrictedinsertion of coil wires of all sizes, including thick bar conductorsinto the stator slots.

The longitudinal slots in stator 10 are shown as having a U-shape withapproximately parallel pole sides (e.g., FIG. 6 sides 62 and 62′). Itwill be understood that the specific shape is chosen only for purposesof illustration herein. Other suitable shapes including those havingvariously tapered or curved sides may be used as appropriate or desired,for example, for specific pole designs or characteristics. Insulationinserts 15 line the walls of slot passages P to electrically isolate theconductors inserted in the stator slots. Inserts 15 may be made, forexample, from plastic sheeting. Inserts 15 may be provided with axialend flanges or shoulder enlargements 15′ (shown in phantomrepresentation), Shoulders 15′ abut or press against stator 10 end faces(e.g., 10′) to prevent movement of inserts 15 parallel to stator axis O.Alternatively or additionally, pins 40 may be used to temporarily tackor hold inserts 15 in position in the stator slots. Pins 40 are removedprior to insertion of conductors (e.g., conductors 16 a or 17 a) in thestator slots. To facilitate this, suitable pin holding and withdrawingstructures may be conveniently disposed adjacent to one or both ends ofstator 10 in the stator assembly processes (not shown).

The assembly processes for making stator 10, may involve the use of acoil-form or mandrel 20. The stator wire coils are first formed onmandrel 20 in a wave configuration, and then transferred into stator 10.Mandrel 20 has seats 21 with radial passages P1 that are open toward theouter surface of mandrel 20. Mandrel 20 fits in the bore of stator 10such that radial passages P1 can be aligned with slot passages P.

Seats 21 are designed to receive longitudinal conductor portions of thewire coil (e.g., portions 16 a and 17 a). The axial ends of mandrel 20are designed to receive conductor lengths (e.g., lengths 16 b and 17 b),which connect the longitudinal portions of the wire coil. Mandrel 20includes suitable mechanisms to transfer out wire coils formed on it.For example, mandrel 20 may include pressers 22 that move in radialdirection R to push out longitudinal conductor portions of the wire coilplaced or formed in seats 21.

In practice, a wire coil is first formed on mandrel 20 while mandrel 20is outside the bore of stator 10 and the mandrel surfaces are readilyaccessible. Then mandrel 20 is inserted in the bore of stator 10 (asshown in FIG. 1) so that radial passages P1 are aligned with stator slotpassages P. Next, pressers 22 are operated to push longitudinalconductor portions (e.g., 16 a and 17 a) radially out of seats 21 intothe aligned stator slot passages P. This push transfer of thelongitudinal conductor portions in radial direction R also moves theconnecting conductor lengths (e.g., lengths 16 b and 17 b) from theaxial ends of mandrel 20 onto the axial ends of stator 10. FIG. 3 shows,for example, a wire coil that has been transferred from mandrel 20 intostator 10.

In alternative stator assembly processes, wave wound wire coils can beformed in stator 10 by dispensing conductors directly into or alongstator slot passages P. A delivery nozzle may be used to deliver ordispense the conductors. Suitable conventional drive mechanisms (notshown) may be used to provide the nozzle and/or stator 10 with thecapability to move relative to each other. The drive mechanisms mayallow relative motion, sequentially or simultaneously, in one or moredimensions. FIGS. 4 and 5 show, for example, a movable delivery nozzle30 that can be used to dispense a conductor (e.g., conductor 16 or 17)along the stator slot passages P. Nozzle 30 operates through the boreand around stator 10.

FIGS. 4 and 5 exemplify the linear movements of nozzle 30. FIG. 4 showsnozzle 30 at position PO1 after it has moved in upward direction 32 todispense a stretch of longitudinal conductor portion 16 a along orparallel to slot 11. Further movement of nozzle 30 in radial direction33 to position PO2 (FIG. 5) pulls or inserts the dispensed stretch oflongitudinal conductor portion 16 a into slot 11.

FIG. 5 also exemplifies the subsequent circular movement of nozzle 30 inan arc 35 along the axial face of stator 10 to deposit the conductorlengths (e.g., lengths 16 b) that lead to the next longitudinal portion16 a of the wire coil (slot 14). Alternatively, nozzle 30 may be keptstationary as it dispenses the conductor lengths while stator 10 isrotated or indexed to the next slot.

Optional guide forms may be employed to assist in mechanically shapingor bending the conductor lengths dispensed by nozzle 30. FIGS. 4 and 5show, for example, guide forms 36 that are aligned with the end faces ofstator 10. Guide forms 36 are suitably shaped to assist in bending thedispensed conductor so that conductor lengths (e.g., lengths 16 b) stayclose to the stator axial faces. The circular motion of nozzle 30 alongarc 35 extends from position PO2 to a radially inward position PO3 aboveslot 14 in preparation for dispensing the next stretch of longitudinalconductor portion 16 a.

It will be readily understood that nozzle 30 can be used to insert acomplete wave wound coil 16 in stator 10 by using suitable combinationsof nozzle movements relative to stator 10 that are similar to thosedescribed above. For example, as a next step nozzle 30 can move downwardfrom position PO3 (in a manner similar but opposite to its upwardmovement in direction 32) to dispense the next stretch of longitudinalconductor portion 16 a for insertion in slot 14.

In addition to dispensing conductor 16, nozzle 30 may also be used todispense conductor 17 or any other number of different conductors thatmay be used to form the stator wire coils. Alternatively, separate oradditional nozzles that are similar to nozzle 30 may be used to dispenseconductor 17. The nozzles (e.g., nozzle 30) may be rotatably mounted onarms or structures that allow continuous adjustment of the nozzleorientation. During the winding or dispensing of the wire coils, thenozzle orientation may be advantageously adjusted as needed so that atall times the dispensed conductor is ejected straight along the nozzleaxis.

After wire coil conductors (e.g., conductors 16 and 17) have beeninserted in stator 10 either by transfer from mandrel 20 or by injectionusing nozzle 30), suitable covers may be placed over the stator slots tomechanically retain the wire coil conductors in position. The covers mayinclude suitable ferromagnetic material sections that enhance passage ofmagnetic flux through the poles of stator 10.

FIG. 6 shows an exemplary slot cover 60 covering the stator slot betweenadjacent poles 63 and 64. Cover 60 is shaped so that it can be installedalong the length of the stator slot and held against respective polesides 62 and 62′. Stator 10 poles also may be designed to includeoptional seats running along the lengths of the poles to receive andhold cover 60 by its ends. FIG. 6 shows, for example, seats 65 and 66running just below the edges or corners C of poles 63 and 64.

Cover 60 includes an insulating portion 61 with lateral extensions orportions 60′ and 60″, which may be made of suitable ferromagneticmaterial. When installed ferromagnetic lateral portions 60′ and 60″provide additional magnetic conducting paths to increase the passage ofmagnetic flux through poles 63 and 64. Lateral portions 60′ and 60″ mayhave widths X and other dimensions or shapes that are designed toreplicate or otherwise function as the conventional pole shoe extensionsthat are omitted in stator 10 design to accommodate insertion of thethick bar conductors in the stator slots.

In the stator assembly processes, slot covers 60 are installed byrunning the appendixes or edges of lateral portion 60′ and 60″lengthwise through seats 65 and 66, until central portion 61 fullycovers slot passage P. FIGS. 7 and 8 show an alternative slot coverarrangement that avoids the use or need for pole seats (such as seats 65and 66) to hold slot covers in position.

Slot covers 70, like covers 60, include insulating central portions 61with ferromagnetic lateral extensions 60′ and 60″. Covers 70 aredesigned to lie over the stator slots between or abutting the edges orcorners C of the adjoining stator poles. Covers 70 that are installedover the stator slots may be fixed in position by mechanically holdingthe longitudinal ends of covers 70. One or more rings that can besecured to the axial faces of stator 10 may, for example, be used tohold the ends of covers 70. FIG. 8 shows an exemplary arrangement of apair of annular rings 71 and 72 that may be used for this purpose. Inthis arrangement, covers 70 extend as downward slats from upper annularring 71. Lower annular ring 72 includes seats 72′ that are designed toreceive and hold longitudinal ends or feet 70′ of the downward slats.Seats 72′ and feet 70′ may be mutually shaped, for example, asconventional tongue and groove joints, for mechanical rigidity of theslot cover arrangement.

In the stator assembly processes, slot covers 70 are installed, forexample, by placing lower annular ring 72 on an axial face of stator 10with seats 72′ aligned with stator slot passages P. Annular ring 71 islowered over the opposing axial face such that covers 70 are insertedinto the stator bore in alignment with the stator slot passages P andtoward annular ring 72. Covers 70 are advanced sufficiently through thebore of stator 10 to allow cover feet 70′ to extend into seats 72′ ofannular ring 72. Annular rings 71 and 72 are then secured to therespective axial faces of stator 10 to hold covers 70 in fixedpositions.

Another slot cover arrangement, which may be used with suitably modifiedstator 10 structures, is shown in FIGS. 9 and 10. In this arrangement, acylindrical sheet 90 is used to cover the entire inner surface of thebore of stator 10. Cylindrical sheet 90 is made of alternatinglongitudinal sections that may be similar to annular ring 71. Thesealternating sections include metal sections 91 that serve as poleexpansions or shoes, and insulating sections 92 that function as slotcovers. Insulating sections 92 may extend away from annular ring 93 tosection ends or feet 92′. Feet 92′ are designed for receipt and holdingin seats 94′ of a lower annular ring 94 that may be similar to annularring 72 (FIG. 8).

Metal sections 91 can be made from suitable ferromagnetic material inthe form of a solid body. Alternatively, metal sections 91 may be madeas a laminate. For example, metal sections 91 may be fabricated bystacking lamination sheets, one on top of the other. Conventionaljoining techniques may then be used to join the stack and form thelaminate. Insulating sections 92 may be made from common insulationmaterial (e.g., plastic material). Annular ring 93 also may be made ofsuitable plastic materials. Conventional plastic injection moldingtechniques may be used to fabricate insulating section 92 and annularring 93 portions of cylinder sheet 90. These techniques may also beconvenient for embedding metal sections 91 in cylinder sheet 90 betweenalternating insulating sections 92.

In the deployment of cylindrical sheet 90, upper annular ring 93 issuspended or held over an axial face of stator 10 so that insulatingsections 92 and metal sections 91 extend downward in longitudinaldirection 92″. Cylindrical sheet 90 is lowered into the bore of stator10 so that insulating sections 92 are aligned with slot passages P andthe metal sections 91 are in contact with top surfaces of the statorpoles (e.g., poles 63 and 64). For mechanical stability of deployedcylindrical sheet 90, ends or feet 92′ of insulating sections 91extending away from annular ring 93 may be mechanically supported at theopposing axial face of stator 10. Lower annular ring 94 with seats 94′,which are designed to receive and hold feet 92′, may be used for thispurpose in a manner similar to that described above for slot covers 70with reference to FIGS. 7 and 8. Annular rings 93 and 94 may be securedto the axial faces of stator 10 to mechanically fix the positions ofinsulating sections 92 over the stator slot passages P.

For increased mechanical rigidity or stability of deployed sheet 90, theupper and lower ends of laminated metal sections 91 also may be pointwelded to the axial ends of the stator 10. Additionally, the mutuallycontacting surfaces of metals sections 91 and stator poles may bedesigned to enhance the mechanical rigidity of deployed sheet 90. Forexample, metal sections 91 may be provided with bottom curved contactsurfaces 91′, and the design of stator 10 may be suitably modified sothat top surfaces (e.g., surfaces 63′ and 64′) of stator poles havecurved shapes conforming to curved surfaces 91′. The conformingcurvature of these surfaces allows good mechanical contact between thepoles and metal sections 91, and yet restricts undesirable slidingmovement of metal sections 91.

This contact arrangement also provides electro-magnetic conducting pathsfor the flow of magnetic flux from the stator poles into the metal 91.Metal sections 91 may be suitably shaped to enhance or optimize the flowof magnetic flux into the stator bore. Suitably shaped metal sections 91may, for example, as shown in FIG. 9, have the shape of conventionalpole expansions or shoes.

In some stator designs, installation of slot covers to restrain wirecoil conductors may not be suitable or required, or may be optional.Accordingly, the slot covers above can be suitably modified. Thesuitable modification may, for example, eliminate or limit theinsulating sections (e.g., 61 or 91) and include only the pole extensionsections (e.g., 60′ and 60″, or 92). Thus in some applications, the slotcovers may be designed to function primarily as pole extensions that canbe attached to poles after insertion or formation of the wire coilsaround them. Conversely, for some other applications the slot covers maybe designed to function primarily as insulating covers limiting oreliminating the pole extension function.

The wide-mouth slot designs and the later-attachable pole extensions ofthe present invention (with or without insulating sections) providegreater design flexibility in dynamo-electric machine manufacture. Thewide mouth slot designs may advantageously be used in other statordesigns that, for example, call for parallel coils or small diameterwire coils (unlike the wave wound thick conductor coils of stator 10).The wide- or open-mouth slot design allows insertion of wire turns intoall regions or portions of the slot volume without geometricalinterference from the pole extensions. Thus higher slot conductivitiescan be achieved.

FIGS. 11-14 illustrate the beneficial use of open-mouth slot designs inmaking stators (e.g., stator 170) with parallel coil configurations(i.e., in which individual coils are wound around individual poles). Theindividual coils may, for example, be pre-formed on a mandrel and thentransferred or inserted radially into the slot passages before poleextensions are attached to the poles.

Exemplary mandrel 100 may be used to pre-form wire coils supported onpockets 120 for insertion or transfer into stator 170. Mandrel 100 has anumber of radial structures or extensions 110 on which hollow coilsupport pockets 120 are slidably mounted. Pockets 120 are designed tofit on both extensions 110 and on poles 20 of stator 170. Pockets 120have trunk portions 120 b between a pair of flanges 120 a. Centralhollows or passages 120 c pass through pockets 120.

When pockets 120 are supported on mandrel 100, lengths of extensions 110extending from shoulders 110″ pass through central passages 120 c ofpockets 120. The sliding position of pockets 120 on structures 110 maybe limited at one end by flanges 120 a acting against shoulders 110″.Suitable mechanical catches (e.g., similar to catches 210) may be usedto secure pockets 120 in position.

When pockets 120 are supported on stator 170, poles 20 pass through thecentral hollows 120 c. Flanges 120 a at the top end of poles 20 may bedesigned and made of suitable ferromagnetic material to serve as poleextensions. Flanges 120 a at the top end include catches 210 that aredesigned to engage matching recesses on stator end board 170′ to holdpockets 120 in position when they are fitted on poles 20.

The number of pockets 120 may correspond to the number of wire coils (orpoles) corresponding to a specific phase in stator 170. Mandrel 100 isdesigned so that the radial axes R through structures 110/pockets 120can be with aligned with stator radii through poles 20.

Individual wire coils 130 may be wound turn by turn, and layer by layer,on trunk portions 120 b using, for example, a conventional flyer arm140. Flyer 140 can rotate around axis R through a subject pocket 120 todeposit or pull wire turns W1 around trunk portions 120 b. Flyer 140 maytranslate along axis R to stratify wire turns W1. Flanges 120 a act asbarriers, which limit the spread of wire turns W1 and coil layers alongtrunk portions 120 b, and thus define the edges of the wound coils.

Mandrel 100 may be indexed relative to flyer arm 140 to present pockets120 in sequence for wire coil winding. Wire coils may be wound by flyerarm 140 successively on all pockets 120. In alternative wire coilwinding arrangements, more than one flyer arm like flyer arm 140 may beused to simultaneously wind wire coils around more than one of pockets120. In a modified mandrel 100, pockets 120 may be rotatable. Suchrotatable pockets (120) may be rotated using suitable conventional drivemechanisms. Pockets 120 may be rotated to draw wire turns aroundthemselves. For wire coil winding on such a modified mandrel 100, a wiredispenser that can translate along axis R may be used to stratify thewire turns drawn by rotating pocket 120.

In assembly line machines, the wire winding configurations (e.g., numberof winding stations or mandrels used, the number of extensions110/pockets 120 on mandrel 100, and the number of flyer arms used) maybe limited in some instances with consideration to stator size, andrequirements of tool clearance and free operating space. In an exemplaryassembly line for manufacturing three-phase stators, three separateworkstations may be used to concurrently process the individual coilsets corresponding to each of the three current phases. In this case,each workstation includes one mandrel. The number of extensions 110provided on each mandrel 100 may be limited and equal the number ofpoles corresponding to single phase (e.g., 4 for the 12-pole stator 170shown in FIG. 12). Limiting the number of extensions in this manner onthe mandrels may provide adequate clearance for conventional tool (e.g.,flyer arm) operation.

In each workstation after a wire coil has been wound around anindividual pocket (120), wire coil leads 150 and 160 may be temporarilyanchored to tabs or anchor posts on the body or the axial faces ofmandrel 100, or optionally on flange 120 a. Conventional leadmanipulators may be used to manipulate leads 150 and 160 for thispurpose (not shown). The lead manipulators used may be similar to thoseshown, for example, in co-assigned and co-owned Luciani et al. U.S. Pat.No. 5,065,503. Such or other lead manipulators may be used to attachinitial and final leads 150, and also uninterrupted leads 160 thatconnect the individual wire coils in a sequence associated with a singlecurrent phase.

After all of the desired individual wire coils corresponding to singlecurrent phase have been pre-formed on mandrel 100 (See e.g., FIG. 12)they may be transferred onto stator poles 20 of stator 170. To initiatethis transfer, mandrel 100 is inserted in the bore of stator 170.Pockets 120/extensions 110 are radially aligned with poles 20 as shownin FIG. 12. Next, pockets 120 are slid in direction 110″ from extensions110 on to aligned poles 20. Suitable mechanisms may be used to slidepockets 120 from extensions 110 onto aligned poles 20. For example,moveable forks 180 may be used to engage and push flanges 120 a indirections 110″ so that pockets 120 slide onto poles 20. Pockets 120bearing the wire coils can slide on to poles 20 smoothly, for example,without geometrical interference from conventional pole extensions orother structures. Suitable pole extensions may be attached later ifdesired.

FIG. 13 shows, for example, pockets 120 that have been transferred ontopoles 20. Mechanical catches 210 engage the matching recesses 210′ tosecure pockets 120 in position over poles 20. FIG. 13 also shows leads150 and 160 that have been repositioned from their temporary positionsto stator end board 170′ using suitable lead manipulators (e.g., thepreviously mentioned conventional lead manipulators). After installationof pockets 120 or a set of poles 20 corresponding to a single currentphase, stator 170 may be transferred to the next workstation forinstallation. of pockets 120 on the next set of poles.

Wire coils having high slot fill densities can be transferred on topoles 20. After the wire coils have been positioned, suitable poleextensions (e.g., metal sections 92) may optionally be attached to poles20.

As a result of applying the principles of the invention, the space ofthe stator slots can be filled with wire turns W1 of coils 130 morecompletely or fully avoiding for example, the geometrical dead spaces inthe leeward shadows of pole extensions found in conventional stators.FIG. 14 shows an enlarged view of area 40 of FIG. 13 illustrating thefill of wire turns W1 in the corners of the pocket 120 adjoining pole20. FIG. 14 also shows optional ferromagnetic inserts 190. Inserts 190,are placed in seats or built into flange 120 a that may be made frominsulating plastics. Inserts 190 abut the top ends of poles 20 and maybe designed to function as pole extensions to enhance and distributemagnetic flux through poles 20.

It will be understood that the foregoing is only illustrative of theprinciples of the invention, and that various modifications can be madeby those skilled in the art without departing from the scope and spiritof the invention. It will be understood that terms like “upper” and“lower”, “front” and “rear”, “upward” and “downward”, and any otherterms relating to direction or orientation are used herein only forconvenience, and that no fixed or absolute orientations are intended bythe use of these terms.

1. A method for the assembly of a dynamo-electric machine component,comprising: providing a casing having poles that are geometricallydefined by slot passages, wherein the slot passages have openingsbetween adjoining poles and wherein the openings have widths that aresubstantially comparable to the widths of the slot passages over theirdepths; and placing wire coils around the poles by moving wireconductors on to the poles from directions that are generally along theradii of the casing, wherein placing wire coils comprises: providing amandrel with seats that can be aligned with the casing slot passages;placing a wire coil conductor on the mandrel, wherein the wire coilconductor passes through the mandrel seats; inserting the mandrel in thebore of the stator casing; aligning the mandrel seats with the casingslot passages; and transferring the wire coil conductor from the mandrelseats into the casing slot passages.
 2. The method of claim 1 whereinplacing wire coils comprises inserting a conductor in a waveconfiguration in the slot passages around the poles.
 3. The method ofclaim 1 further comprising: lining the walls of the slot passages withinsulating inserts; and using removable pins to temporarily tack theinsulating inserts prior to insertion of a conductor in the casing slotpassages.
 4. The method of claim 1 further comprising installing poleextensions abutting the poles after placing the wire coils around thepoles.
 5. The method of claim 1 further comprising installing slotcovers over the slot passages after placing the wire coils around thepoles.
 6. The method of claim 5 wherein installing slot covers comprisesplacing a slot cover that has a pair of pole extension portions and anintervening insulating portion over a slot passage so that the pair ofpole extension sections respectively abut the two poles adjoining theslot passage.
 7. The method of claim 5 wherein providing a casing havingpoles comprises providing a casing in which the poles have seats forreceiving edges of the slot covers.
 8. The method of claim 5 furthercomprising holding the installed slot covers by their ends.
 9. Themethod of claim 5 wherein installing slot covers comprises inserting acover structure in a bore of the casing, wherein the cover structurecomprises alternating insulating and pole extension sections, andwherein inserting the cover structure comprises: aligning the coverstructure so that the insulating sections cover the slot passages andthe pole extension sections abut the poles; and securing the position ofthe aligned cover structure with respect to the casing.
 10. The methodof claim 1 wherein the wire coils comprise conductors having crosssections that are comparable to the widths of the slot passages.